This report considers ground vehicle lateral/directional stability which is of primary concern in traffic safety. Lateral/directional dynamics involve yawing, rolling and lateral acceleration motions, and stability concerns include spinout and rollover. Lateral/directional dynamics are dominated by tire force response which depends on horizontal slip, camber angle and normal load. Vehicle limit maneuvering conditions can lead to tire force responses that result in vehicle spinout and rollover. This report describes accident analysis, vehicle testing and computer simulation analysis designed to give insight into basic vehicle design variables that contribute to stability problems. Field test procedures and results for twelve test vehicles are described. The field test results were used to validate a simulation model which was then analyzed under severe maneuvering conditions to shed light on dynamic stability issues associated with spinout and/or rollover. Vehicle parameter measurements for an additional 29 vehicles are also included that, when combined with the twelve field test vehicles, illustrate the distribution of stability relevant characteristics for a wide range of cars, light trucks and utility vehicles. Simulation analysis for selected vehicles is used to show the relationship between vehicle characteristics and lateral/directional stability problems. The results of vehicle testing and simulation analysis indicate that a vehicle that has both a relatively low ratio of track width to center of gravity height and is equipped with tires which have a relatively high peak coefficient of friction will have a propensity to rollover during steering maneuvers on a flat surface. Vehicle testing and computer simulation analysis also indicate that directional stability is significantly influenced by the relationship between vehicle weight distribution and lateral load transfer distribution that is greater than or equal to the percent weight on the front axle. Two of the test vehicles which had relatively low front axle lateral load transfer distribution were found to have a spinout tendency, and simulation analysis showed that directional stability can be directly influenced by shifting the lateral load transfer distribution between the front and rear axles.

  • Supplemental Notes:
    • Sponsored by the National Highway Traffic Safety Administration, Washington, D.C.
  • Corporate Authors:

    Systems Technology, Incorporated

    13766 South Hawthorne Boulevard
    Hawthorne, CA  United States  90250
  • Authors:
    • Allen, R W
    • Szostak, H T
    • Klyde, D H
    • Rosenthal, T J
    • Owens, K J
  • Publication Date: 1992-6


  • English

Media Info

  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 301 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00719464
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: STI-TR-1268-1, HS-807 956
  • Contract Numbers: DTNH22-88-C-07384
  • Files: HSL, TRIS, USDOT
  • Created Date: Mar 22 1996 12:00AM